Electron device



E. F. HENNELLY ELECTRON DEVI CE Filed Aug. 29, 1921 Inventor: Edward F. Hennelly TEWWM His Attorney Patented Aug. 25, 1925.

- UNITED STATES PATENT OFFICE.

EDWARD F. HENNELLY, or sonENEcrAnY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, 13 CORPORATION on NEW YORK.

ELECTRON DEVICE.

Application filed August 29, 1921. Serial No. 496,727.

To all whom it may concern:

Be it known that I. EDWARD F. HENNEL- LY, a citizen of the United States, residing at Schenectady. county of Schenectady, State of New York, have invented certain new and useful Improvements in Electron Devices, of which the following is a specification.

My present invention relates'to the structure of electron discharge devices. My improvement is especially adapted to the construction of devices described by Dr. Albert A. Hull in the Journal of the American Institute of Electrical Engineers for September, 1921, page 715, and known as magnetrons, although it is applicable to various types of electron devices.

In these devices an electron current between an electron emitting cathode and a surrounding anode is controlled by an electro-magnetic field parallel to the cathode which constrains the electrons to move in spiral paths. In the mostelficicnt operation of this device, it is desirable to construct and support the electrodes in such a way that the magnetic winding may be brought close to the space between the electrodes and it is likewise important to avoid a distortion of the electrostatic field at the electrodes when the device is in use.

In accordance with my invention have provided a structure for supporting the anode whereby both these desirable conditions are satisfied and at the same time other advantages are gained, for example, the anode is securely, held in the bulb by supports aifording a path of low heat conductivity. These and other features of my invention will be pointed outin connection with the accompanying drawings which show in Fig. 1 in perspective one embodiment of my invention and in Fig. 2 a modi fication.

The device shown in Fig. 1 comprises a container 3 consisting ordinarily of glass into which is sealed a cathode 4 which commonly consists of a. rectilinear filament of tungsten or other suitable refractory metal. This cathode 4 is connected to leading-in wires 5 and 6 sealed into the envelope in the usual way. Interposed between the wire 5 and the cathode is a resilient spiral spring 7 which holds the cathode filament taut. The anode 8 consisting of molybdenum, tungsten or the like, is commonly cylindrical in shape a slit being provided as indicated, and is symmetrically located about the cathode 4. The anode is only a very httle smaller in diameter than the container 3 and preferably is symmetrically spaced w1th respect to the cathode and container so that these three elements constitute surfaces of revolution about a common axis. Located in the space between the anode S and the envelope 3 are helices 9, 10, preferably consisting of tungsten wire although of course other suitable refractory material may be used for the same. The helices may be connected to the anode 8 in any suitable way for example, as shown, by being threaded over wires 11,12 which are fastened to the anode. The diameter of each helix is about equal to one-half the difference between the diameters of the anode and the container so that they substantially fill the space between the anode and the containers and supportthe anode by frictional contact with the inner wall of the container. The number of turns in the helices per unit length may vary considerably depending upon the proportions of the device, ordinarily about 5 to 30 turns per unit are used. Each turn of the helices makes contact with the anode and the glass container respectively at only a point so that when the anode is heated the thermal conductivity of the path through the helices is low enough to prevent excessive heating of the bulb. This result is so cured together with a secure anchorage for the anode which will resist displacement of the anode or breakage under ordinary conditions of use or handling to which the device is subjected.

Various other frictional devices for holdmg the anode may be positioned within the confines of the anode surface. For example, in Fig. 2 I have shown fragmentally an electron discharge device in which the anode 8 is supported by spring holders 14 consisting of lengths of wire sprung over notched supports 15 connected to the anoue. These re silient holders make contact with the anode and the adjoining glass wall at only a very few points. Instead of solely anchoring the anode by frictional engagement of the holders with the glass wall, indentations such as shown at 16 may be used in the glass wall which engage with the looped anchors 13 and prevent displacement of the anode.

When the device is to be used for moderate voltages a relatively short anode lead projecting beyond the expanse of the anode is permissible, as for example, the anode conductor 17 of Fig. 1 which is connected to the anode 8 by a flexible wire 18. For very high voltage an anode lead which does not roject beyond the anode as shown at 19, ig. 2, preferably is employed. 'lhese anode conductors being sealed into the tube wall, materially assist in holding the anode in place. A bufi'er spring 20 is preferably used to protect the glass seal from shock and strain.

It will be observed that by use of supports constructed and positioned in accordance with my invention, the anode is brought close to the wall of the container so that the most economical utilization of the magnetic field produced by a winding (not shown) exterior to the device is secured.

That 1 claim as new and desire to secure by Letters Patent of the United States, is 2-- 1. An electric discharge device comprising a container, cooperating electrodes there- 1n and supporting means concentrically located between one of said electrodes and said container, said supporting means being disposed upon and confined substantially to the exterior surface of said electrode and adapted to engage frictionally with interior surface of said container immediately adjacent said electrode surface.

2. An electric discharge device comprising a glass container, cooperating electrodes therein, one of which is cylindrical in shape and symmetrically spaced with respect to the other electrode and means disposed upon and confined substantially to the exterior surface or" said cylindrical electrode and :irictionally engaging with said container for holding said cylindrical anode in fixed position within said container, said holding means being positioned with respect to said anode so as not to interfere with the distribution of an electrostatic field which may be produced at said anode.

3. An electric discharge device comprising a cylindrical evacuated tube, a rectilinear cathode axially disposed in said tube, means for heating said cathode, an anode symmetric with respect to both said cathode and tube, and means positioned within the confines of the outer surface of the anode and adapted to contact frictionally with points on the inside surface of said evacuated tube immediately adjacent the outer surface of said anode.

4. An electron tube comprising an evacuated cylindrical container, a cathode therein, an anode arranged in circular symmetry about said cathode and a plurality of compressible holders disposed within the confines of the surface of said anode and engaging with said container intermediate the extremities of said anode at points circumferentially spaced apart.

5; An electron discharge device comprising a container, an electrode system disposed therein, one member of said System having an external form similar to the interior configuration of said container and being but slightly smaller in diameter than said container and compressible spring devices disposed upon and confined to the exterior surface of said member and adapted to contact with points on the inside of-said container immediately adjacent the surface of said member.

6. An electric discharge device comprising a container cooperating electrodes therein, one of which has an external form similar to the interior configuration of said container and being but slightly smaller in diameter than said container, and compres sible spring devices disposed upon and confined to the exterior surface of said electrode and adapted to contact with points on the inside surface of said container.

7. An electric discharge device comprising a substantially cylindrical container, electrodes therein, one of which is substantially cylindrical and has a slightly smaller diam eter than said container, and spring holders for said cylindrical electrode, said holders being located in the space between said electrode and said container and mounted upon but not extending substantially beyond the confines of the exterior surface of said electrode, said holders being adapted to contact with points on the inside surface of said container.

In witness whereof, I have hereunto set my hand, this 23rd day of August, 1921.

EDWARD F. HENNELLY 

